The evidence that e-cigs attract low risk kids, many of whom progress to cigarettes, just keeps piling up

Kaitlyn Berry and colleagues just published  “Association of Electronic Cigarette Use With Subsequent Initiation of Tobacco Cigarettes in US Youths” in JAMA Network Open that further strengthens the overwhelming case that e-cigarettes are expanding the tobacco epidemic by bringing low risk kids who are unlikely to start using tobacco with cigarettes. In addition, they show that e-cigarettes are a gateway to cigarettes, with a stronger effect for e-cigarettes than other tobacco products. 

The effect of e-cigs as a gateway for cigarettes was very large for low risk kids, an adjusted odds ratio of 8.6, compared to the odds ratio of 3.5 for the intermediate-to-high-risk kids.

They also highlight the importance of other tobacco products as starter products for kids, although the differential effect on low-risk kids seen with e-cigarettes is not present for the other products.

They also estimate the number of kids who have tried cigarettes as a result of e-cigarettes – 179,000 – and the number of current smokers because of e-cigarettes – 43,000.  Their careful analysis of this question based on individual-level data is more evidence that the conclusion Levy and colleagues drew (based on aggregate data on cigarette smoking) that e-cigarettes were accelerating the decline in cigarette smoking is wrong.

There have been so many of these studies that I have lost count and all of them show a gateway effect, with the biggest gateway effect in e-cig-friendly England.

It’s time for the e-cig enthusiasts to accept these results and stop trying to explain them away.

Here is the abstract:

Importance:  The use of electronic cigarettes (e-cigarettes) and other noncigarette tobacco products may increase the odds of cigarette initiation, even among low-risk youths.

Objective:  To evaluate the associations of prior e-cigarette use and other tobacco product use with subsequent cigarette initiation within 2 years of follow-up.

Design, Setting, and Participants:  In this prospective cohort study, data from waves 1 through 3 of the Population Assessment of Tobacco and Health Study (2013-2016) were used to assess youths aged 12 to 15 years who had never used cigarettes, e-cigarettes, or other tobacco products at wave 1. This was a nationally representative study of the US population. Data analysis was conducted in 2018.

Exposures: First noncigarette tobacco product used (none, e-cigarette, or other tobacco product) between wave 1 and wave 3.

Main Outcomes and Measures: Ever cigarette use and current cigarette use at wave 3.

Results:  In the sample (N = 6123), respondents were 49.5% female; 54.1% non-Hispanic, white; and the mean (SD) age was 13.4 (1.2) years. Of these, 8.6% reported e-cigarettes as their first tobacco product, while 5.0% reported using another noncigarette product first; 3.3% reported using cigarettes first. Cigarette use at wave 3 was higher among prior e-cigarette users (20.5%) compared with youths with no prior tobacco use (3.8%). Prior e-cigarette use was associated with more than 4 times the odds of ever cigarette use (odds ratio, 4.09; 95% CI, 2.97-5.63) and nearly 3 times the odds of current cigarette use (odds ratio, 2.75; 95% CI, 1.60-4.73) compared with no prior tobacco use. Prior use of other tobacco products was similarly associated with subsequent ever cigarette use (OR, 3.84; 95% CI, 2.63-5.63) and current cigarette use (OR, 3.43; 95% CI, 1.88-6.26) compared with no prior tobacco use. The association of prior e-cigarette use with cigarette initiation was stronger among low-risk youths (OR, 8.57; 95% CI, 3.87-18.97), a pattern not seen for prior other product use. Over the 2 years between 2013 and 2014 and 2015 and 2016, 21.8% of new cigarette ever use (178 850 youths) and 15.3% of current cigarette use (43 446 youths) among US youths aged 12 to 15 years may be attributable to prior e-cigarette use.

Conclusions and Relevance:  This study's findings support the notion that e-cigarette use is associated with increased risk for cigarette initiation and use, particularly among low-risk youths. At the population level, the use of e-cigarettes may be a contributor to the initiation of cigarette smoking among youths.

The full citation is Berry KM, Fetterman JL, Benjamin EJ, Bhatnagar A, Barrington-Trimis JL, Leventhal AM, Stokes A.  Association of Electronic Cigarette Use With Subsequent Initiation of Tobacco Cigarettes in US Youths.  JAMA Netw Open. 2019 Feb 1;2(2):e187794. doi: 10.1001/jamanetworkopen.2018.7794.  It is available here.